© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center Creating Geometry in GAMBIT

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center Preliminaries-1  Objective: Create and mesh the fluid region for flow problems and solid regions for heat transfer (and structrual analysis for Fidap Users). Typically accomplished by constructing and working with lower order entity objects and volume primitives.  Terminology: Vertex - a point Edge - a curve that is defined by at least 1 vertex (in the case of 1 vertex, the edge forms a loop) Face - a surface (not necessarily planar) bounded by at least 1 edge (in the case of 1 edge, the edge forms a loop) Volume - a geometric solid (as in a solids model), also can be thought of as an “air tight” set of bounding faces.

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center Preliminaries-2  Identification: Standalone entities assume following color scheme: Vertex (white), Edge (yellow), Face (light blue), Volume (green), Group (dark green) When an entity is connected, it is taking the highest (dimensionally) entity color  Undo/Redo: 10 levels of undo by default. Undoes geometry, meshing, and zoning commands. Description window provides command to be undone when mouse is passed over undo button. Left click to execute visible button operation. Right click to access options.

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center General Operations: Coordinate System  Coordinate system Cartesian, Cylindrical and Spherical systems Using Offset/Angle or Vertices for location/orientation “Active” coordinate system is default in all forms Grid creation with “snapping” of vertices -Recommended for simple geometries only Creation of rulers

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center General Operations: Move/Copy  Move/Copy Operations: Translate: ( inputs are  s ) Reflect: Plane normal to vector (x,y,z) Angle Vector Rotate: Scale:  Options: Connected geometry can also be Moved Mesh can be copied linked or unlinked

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center General Operations: Vector Definition Form  Vector Definition form is used in: Rotate and Reflect (in Move/Copy) Sweep and Revolve (in Face/Volume Create) Methods: Coordinate system axis Two existing vertices An existing Edge Two points defined by coordinates Screen View Magnitude option allows size of vector to be defined.

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center General Operations: Align  Align Align is an alternative to Move - translate (+rotate). It uses vertices on the start and final position to move the object Method of increased alignment with the use of vertex-pairs Connected geometry can be included RotationPlane alignmentTranslation

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center General Operations: Connect  Connect (Real) Vertices, Edges and Faces can be connected The operation eliminates all duplicate entities and reconnects upper topology Only entities within the ACIS tolerance will be connected Existing mesh will be preserved Connect Edges Copy +Translate Two Edges One Edge One Face

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center General Operations: Disconnect  Disconnect (Real) Vertices, Edges and Faces can be disconnected The operation recreates duplicate entities and reconnects upper topology Several options exists Disconnect Two Edges One Edge Edge + Vertices

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center General Operations: Delete  Delete Default deletes geometry and lower geometry. Option to keep lower geometry (e.g., delete face but save edges)

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center General Operations: Misc.  Summarize/Query/Total Summary of vertex coordinates,lower topology, mesh information, element/node labels, etc. Checks for valid ACIS geometry Query: useful to associate geometrical objects with object names Get total number of Entities  Modify Color/Label Modify entity colors Change entity label

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center Geometry Creation  ACIS - geometry engine (“kernel”) Provides tools for “bottom-up” creation by: Vertex:Add, Grid Snap, etc. Edge:Line, Arc, Ellipse, Fillet, B-spline, etc. Face:Wire Frame, Sweep, Net, etc. Volume:Wire Frame, Sweep, Face Stitch, etc. Provides tools for “top-down” creation by Face Primitives:Rectangle, Circle, Ellipse Volume Primitives:Brick, Cylinder, Sphere, etc. Volume/Face Booleans:Unite, Subtract, Intersect Volume/Face Decompose:Split Geometry creation typically involves use of all tools.

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center “Bottom Up”: Vertex Creation-1  Real Vertex creation By coordinates Cartesian, cylindrical and spherical coordinate systems Also available in virtual geometry On edge If the intention is to split the edge, the Edge-Split form should be used instead On face Useful to create edges on surface for a virtual split In volumes Not frequently used At edge-edge intersections Vertex is not connected to either edge Split edge with vertex for connectivity

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center “Bottom Up”: Vertex Creation-2  Import point data, File   File format: ICEM Input Vertex Data Format is similar, curve information is not needed n pc n c x 1 y 1 z 1 x 2 y 2 z 2 : x n y n z n Where:n = n pc * n c is the total number of points n pc is the number of points per curve n c is the number of curves x i y i z i are real or integer vertex coordinates

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center “Bottom Up”: Edge Creation-1  Real Edge creation Straight line Multiple edges can be created by selecting multiple vertices. Arc, Circle Face create counterparts available Creation Methods s Three vertices on the edge s Using Center and End-points s Using Radius and Start/End Angles (Arc Only)

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center “Bottom Up”: Edge Creation-2  Real Edge creation Elliptical Arc Created by three vertices Conic Arc Created by three vertices Major Vertex On Edge Vertex Center Vertex End Angle Start Angle Shoulder Vertex End Vertex Start Vertex

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center “Bottom Up”: Edge Creation-3  Real Edge creation Fillet Arc Creates a fillet out of a corner NURBS Third-order by default Use tolerance for the approximate option Edge 1 Edge 2 Radius

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center “Bottom Up”: Edge Creation-4  Real Edge creation Revolve Vertex Select one or more vertices to rotate Specify Angle Axis is defined using Vector Definition Panel Project Edge on Surface Limited to single edge and face Direction defined in Vector Definition Panel

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center “Bottom Up”: Face Creation-1  Real Face creation Wire Frame Creates real and virtual faces All edges have to be connected into one loop Number of edges and order of picking are not important If all edges are co-planar — creation is always successful For non-coplanar edges: s The number of edges has to be 3 or 4 s Edges cannot have the same tangent at the connecting vertex create real face by wire frame co-planar edges real face +

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center “Bottom Up”: Face Creation-2  Real Face creation Parallelogram defined by three vertices Polygon Selection order is important. 5 or more vertices must be coplanar. Vertex rows Tolerance input Skin Topologically parallel edges Edges have to be picked in order Both ends of all edges can not coincide Net Topologically intersecting edges

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center “Bottom Up”: Face Creation with Revolve  Real Face creation Revolve Using an edge, an angle and a revolving vector Use vectors for definition of the axis of revolution Basic edge can coincide with axis axis of revolution

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center “Bottom Up”: Face Creation with Sweep  Real Face creation Sweep Rigid option s The driving Edge/vector can be anywhere in the domain Perpendicular option s The driving edge/vector has to start in the “plane” of the curve or face edge path edge path Draft edge path Twist 30 deg

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center Face Primitives  Face Primitives Dimensions and Plane/Direction must be specified Rectangles Circles Ellipses

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center “Bottom Up”: Volume Creation-1  Real Volume creation Stitch Create volumes out of connected faces Available in virtual geometry Order of picking not essential Voids not allowed Revolve Using a face, a revolving vector and an angle Use edges or vectors for definition of the axis of revolution ten connected faces one volume axis of revolution

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center “Bottom Up”: Volume Creation-2  Real Volume creation Wire Frame Create volumes from connected curves Number of edges and order of picking is not important Voids and seamless volumes and faces cannot be created Same limitation as face wire frame creation, for each face 36 connected edges one volume

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center “Bottom Up”: Volume Creation with Sweep  Real Volume creation Sweep Rigid option s The driving edge/vector can be anywhere in the domain Perpendicular option s The driving edge/vector has to start in the “plane” of the curve or face face path DraftTwist face path face path

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center Volume Primitives-1  Real Volume Primitives Brick Width (X), Depth (Y) and Height (Z) The Width (X) value is used for Y and Z if no other input is given. 10 different preset positions (each octant plus center) Cylinder and Frustum Height and two cross-sectional radii (3rd radius for frustum) The Radius 1 value is used for remaining radii if no other radius input is given. 9 different preset directions (three in each axis)

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center Volume Primitives-2  Real Volume Primitives Prism and Pyramid Corresponding to input of cylinder and frustum Number of sides 9 different preset directions (three in each axis) Sphere - only one radius Torus Major and cross-sectional radii Three axis locations

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center Boolean Operations: Unite  Real Face/Volume Boolean Unites The order of picking is not important (except for labeling) Retain - keeps copies of the entities Unite Faces All faces must be coplanar or have matching tangents. Unite Volumes A B A + B A B

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center Boolean Operations: Subtract  Real Face/Volume Boolean Subtract The order of picking is important Retain - keeps copies of entities Subtract Faces All faces have to be coplanar Subtract Volumes A B A - B B - A A - BB - A A B A B Multiple entities can be entered in second list box.

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center Boolean Operations: Intersection  Real Face/Volume Boolean Intersect The order of picking is not important (except for labeling) Retain - keeps copies of entities. All entities must intersect each other. Intersect Faces All faces have to be coplanar Intersect Volumes B A B A

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center  The Split Operation: Employs the intersection of two geometric entities to divide one or both objects into two or more pieces. Useful for decomposing complicated geometries into smaller, simpler ones.  Edge Split Split an edge into two or more edges Resulting edges are, by default, connected. Edges can be split with: Point - specify U Value between 0 and 1 where edge will be split. s Use 0.5 to split edge in half. Vertex - must already be created. Edge s Must already be created s Bi-directional option results in both edges being split at point(s) of intersection. Geometry Splitting- Edges

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center Geometry Splitting- Volumes  Real Volume Boolean Split The order of picking is important Volume/Volume splits two volumes Bidirectional Split three volumes Split A with B B A two volumes Split B with A two volumes Volume/Face splits “Target” Object “Tool” B A B A

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center  Real Face Boolean Split The order of picking is important Faces do not need to be coplanar example: coplanar face splits The Bidirectional Face split is not yet supported.  In general, for all splits (edges, faces, volumes): “Tool” entities are, by default, deleted after split is performed Retain option prevents “Tool” entities from being deleted. By default, resulting objects are connected. Geometry Splitting- Faces Split A with B Split B with A Two Faces “Target Object” “Tool”

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center  The appropriate operation to use can depend upon final geometry required. Subtract Cut-away shows one volume results s Cannot mesh core region s Flow/Heat Transfer in annular region only Split Two connected volumes result s Cut-away shows that both annular and core regions can be meshed. s Flow/Heat Transfer possible in both regions Subtract + Retain “Tool” (inner cylinder) Two disconnected volumes result, appears same as split Duplicate faces appear at interface s Non-conformal mesh can result s Useful for multiple reference frame problem (Fluent) Split vs. Subtract Start with two disconnected cylinders

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center  The appropriate operation to use can depend upon the need to create additional surfaces for: defining boundary conditions controlling meshing distribution Bidirectional Split vs. Unite Unite  Unite One volume results Cut-away shows no interior faces BiDirectional Split  Bidirectional split Three connected volumes result Cut-away shows multiple interior faces which can be used to: define internal boundaries help control mesh distribution in volume Total represented volume is the same Start with two disconnected cylinders

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center Split/Boolean Characteristics: Imprinting  Special cases For Unite or Bidirectional Split Any other enclosed connected volume will get a bidirectional split Special for volume or face split GAMBIT will split the volume using all connected internal faces/volumes, even though only one was picked one volume two volumes Unite A with B B A C B will make an “imprint” on C two connected faces Split Volume with one Face A + B A and C connected, B separate C

© Fluent Inc. 10/20/ Introductory GAMBIT Notes GAMBIT v2.0 Jan 2002 Fluent User Services Center Volume Blends  Real Volume Blends Blend - create fillet/rounded edges Pick a volume Pick the edges that need a blend and specify radius Pick vertex (if needed) and specify radius using the Setback option Bulge option is not recommended for hexahedral meshing Bulge option Setback option